1. Field of the Invention
The present invention relates to a composition for permanent hairwaving containing as a keratin-reducing active ingredient 1-thio-.beta.-D-glucose or its salts, particularly 1-thio-.beta.-D-glucose-ammonium salts or sodium salt dihydrate, as well as a process for permanent hairwaving using this composition.
2. Prior Art
It is known that the customary method for performing permanent hairwaving is based on two treatment steps: in the first step the cystine-disulfide-bridges of the hair keratin are split by the effects of a preparation which contains a reducing substance (waving composition). Then the hair is shaped as desired. In a second step, cystine-disulfide-bonds are closed again through the use of a neutralizer, i.e. a preparation containing an oxidizing active ingredient.
As the pioneering work in German Patent Applications 948 186 and 972 424 shows, thioglycolic acid is used as the classic permanent reduction agent, for example as ammonium or mono-ethanol amine salt. Other conventional active reducing substances are inorganic sulfites, 2-mercapto propionic acid (thiolactic acid); 3-mercapto propionic acid, certain mercapto carboxylic acid esters, cysteine and derivatives of these compounds.
However, all of these solutions have a number of disadvantages. Alkaline adjusted preparations based on thiocarboxylic acid exhibit damage to the hair despite sufficient effects, which for example presents itself in increased cases of hair breakage. Frequently these types of solutions stress the scalp by undesirable reactions. The mercapto carboxylic acid esters, which make hairwaving possible even in the neutral and slightly acidic range, are not satisfactory with regard to their tolerance by the skin and their sensitizing risks.
The use of the thiolactic acid makes it possible to solve some of the problems mentioned. However, thiolactic acid produces a weaker shaping effect than the customarily used thioglycolic acid.